[Users] Synchronization and MoL

[Ian Hinder]

Hi,

When using MoL with Carpet, in which situations should I 'SYNC' my
grid functions?  In the MoL documentation, it says that MoL handles
all SYNCing across processors, so I don't need to worry about it.  So
I take this to mean that when I compute my RHS quantities on the
interior of the grid in MoL_CalcRHS, I do not need to SYNC them in the
schedule file.  This agrees with what I find in the various example
thorns.

I currently apply my boundary conditions to the RHS variables in
MoL_RHSBoundaries; do I need to SYNC them?  I am not interested in the
RHS variables being correct at the end of a time step, just that the
evolution is correct.  All the examples I can find in Cactus and
Carpet use the Boundary interface, rather than setting the RHS
variables directly.  These seem to SYNC the evolved variables in the
routine they call in MoL_PostStep.

-- 
Ian Hinder
hinder at gravity.psu.edu
http://www.gravity.psu.edu/~hinder